Boiler section



L. N. HUNTER Jan. 23, 1940.

BOILER SECTION Filed Feb. 10, 1937 2 Sheets-Sheet 1 Louis ]V.Hunfer 6,4

Jan. 23, 1940. HUNTER 2,188,266

BOILER I SECTION Filed Feb. 10, 1957 2 Sheets-Sheet 2 INVENTOR PatentedJan. 23, 194 0.

BOILER SECTION Louis N. Hunter, J ohnstown, Pa., assignor to TheNational Radiator Company, a corporation of Maryland ApplicationFebruary 10, 1937, Serial No. 125,045

' 1 Claim. (01. 122-5225) This invention relates to boiler sections, andparticularly to a boiler section provided with internal means forreducing the moisturecontent of the steam generated in the boilersection. The

'invention is primarily applicable to sectional boilers as distinguishedfrom boilers of single or one-piece construction.

It is generally recognized that in the generation of steam in a boiler acertain amount of water in the form of small drops or particles iscarried along with the steam. It is also generally recognizedthat thepresence of such water particles or drops in the steam is not desirable.Steam which is relatively free from such susi pended particles isfrequently referred to as dry steam,whereas steam which contains aconsiderable amount of such water is referred to as moist or wet steam.

The plane of separation between the water space in a boiler and thesteam space is quite generally termed the water line and is also knownas the steam releasing area or steam releasing surface. When steamleaves the. water surface or the water line, it has a tendency to carrywith it the small particles or droplets of water above referred to. Onefactor which determines the amount of water carried off is the rate offiring of the boiler. The higher the firing rate the greater the rate atwhich steam is generated and there is, therefore, a greater} velocity ofthe steam leaving the surface of the water, tending to entrain a greateramount of water. Another factor which determines the amount of moisturein the steam is the relation of the steam releasing area in proportionto the capacity of the boiler. If the steam-releasing area of the boileris relatively small as compared with the amount of steam beinggenerated, the steam will leave the water line at a greater velocitybecause of its concentration over a small area and, therefore entrainmore water. e

A third factor affecting the carrying off of small particles of water isthe circulation of the water in the boiler below the water line. As the,

steam is generated, convective currents, of course, are set up in thewater, resulting in the presence of upwardly moving currents of waterand downwardly moving currents. The upwardly moving currents are thehotter ones and steam is released more rapidly over these areas ofupwardly moving currents than at other points on the surface of theWater. This results in the tendency for the steam generated at thesepoints to carry a greater moisture content and this is aggravated by thecurrents of water itself. The heating engineer should bequalified todetermine the proper size of boiler so that it does not have to be firedat an excessive rate, and the boiler designer endeavors to provide anadequate steam-generating surface for the amount ofv steamrequired.

The third factor, however, i. e., the movement of the currents of waterwithin the boiler itself, is inherent to the operation of the boiler andthe elimination of wet steam from this source .has heretofore presenteda problem. This is particularly true in the case of sectional boilersused in heating plants where the requirements on the boiler fluctuateWidely with variations in the outside temperature and where, foreconomical purposes, the boilersections should be designed for useeither in hot water, steam or vapor heating systems.

According to the present invention, it is proposed to provide bafileswhich are generally inclined with respect to the water line locatedacross the areas of greatest upward movement of the water, i. e'., theareas where steam is generated at the highest rate,.so arranged that allof the steam generated this area is deflected in a generally horizontaldirection and then caused to reverse its flow at a sharp angle one ormore times before reaching the steam take-01f of the boiler. Bydeflecting the direction of flow of the steam sharply, the entrainedparticles of water having a greater mass, change their direction lessreadily and are, therefore, removed by this kinetic action from thesteam. The baflles are so constructed that the steam cannot avoid theeffect of them so long as a proper water line is maintained within theboiler. At the same time, their arrangement and disposition is such thatif it is desiredto use the boiler in a water heating system instead of asteam heating system, they offer no impediment to a proper circulationof. water through the boiler, nor will. they become loaded with solidsprecipitated from the water.

The invention may be readily understood by reference to the accompanyingdrawings which illustrate one typical form of section to which thepresent invention is applicable having my in vention applied thereto.

In the drawings:

Figure 1 represents a vertical transverse section Figure 2 is atransverse section in the plane of line II--II of Figure 1, and

Figure 3 a fragmentary sectional view similar to Figure 1 representingthe upper portion of one side of the boiler section, the view being on ascale larger than Figure 1.

In the drawings, 2 designates generally a boiler section having an upperchamber 3. The plane of the normal water line of the boiler is indicatedat 4. The portion of the chamber 3 above the water line constitutes asteam chamber, while the portion below the water line constitutes awater chamber. The' section is shown as having a nipple port 5 in theside face thereof, the nipple port being centrally positioned withrespect to the vertical axis of the section and being so disposed that apart of the nipple port is below the water line and a part of it abovethe'water line. Formedin the top of the section at the center thereof,is a steam take-ofi connection 6. The boiler section below the chamber 3isf ormed with flue parse sages therethrough, the particular sectionillustrated being shown as having a centralflue l and a side flue 3. Thepresence of these flues forms on the'inte'rior of the section, waterchan nels'll between thefliles 1 and'B, and water channels 'IWbetfeenthef'fiues 8 andthe outsideof the boiler. Below thefi'ues l and 8 thereis a water space H' which tommumcats with water spaces [Tin theleg'porti'oris or the; section. It

will'b'e' understood that this section is merely typical'of'the'generalclassof sections to which the" present inventionperta'insand that the in-v vention' is not restricted to the particulararrangement of fluesorbthermattersofdesign;

' In the operationbf the boiler sections steam is genera'tedfmuch'morerapi'd-ly the water r channels than inthe'water channels It, so thatth'ere"is"an area at'the'water line over these channels 9"wheresteamleaves the' water at a relatively higher rate than it does fromother areas over the water line. Also there is greater turbulence at thewater line by reasonjof the upward motion of the currents of water'underlying the surface; "In Figure 3 the arrows below the" water lineindicategenerauyftne direction of'fiow'of the waterbelow' the waterline, while the arrows in thest'earri space indicate the directionoffiowofthe steam.

JAbco'rdingtothe present invention, I provide in the boiler over thoseareas whre'steam is generated'at a higher rate, baliles 'ISI There aretwo baill'esl3' shown, one'fbei'ng located at each sid'e' of theverticalcenter'line of the section, one of'thein being locatedinthe areaof the boiler over one of the waterbirculating passages 9, and

the'otherof them being similarly locatiecl in the area over theotherpassage 9;" These baflles i ewhi'ch are generally inclined andpreferably curved, have the "lower end thereof terminating below'thepla'ne of the normallwater line. They are inclinedorjcurved upwardly andoutwardly from a point" below the normal water line to-" Ward the olitel'wall's Of the' sec'tion. They 8X- ten'd across the full depth of the"section and, in

the case of a cast iron section, are integrally 1 cast. The steam whichis generated at ajhigh rate in the area beneath the bafiles l3 risesfrom the surface of the water and'is deflected by the 'baffies in ahorizontal direction away from the' I steam outlet connection 6.

When the steam clears the bafile, it rises upwardly and then turnshorizontally backtowardthe center of the boiler V soj that in clearingthe baflie it turns 'through an surface of the water to the outlet.

arc of 180. In leaving the take-off t, it must again change itsdirection of flow 90 from a horizontal line. In so changing itsdirection of flow, entrained water particles, being of greater mass,change their direction less readily and are, therefore, thrown out ofthe steam.

By reason of the fact that the bafiles have their inner lower endsterminating below the normal water line, it is impossible for any steamleaving the water surface in this particular area to by-pass the bafileand flow directly from the Steam is generated at a relatively slowerrate in that area of the boiler between the two bafiles and this steamcan flow without substantial deflection directly to the outlet. Theturning of the steam through an angle of 180 as it clears the bafileresults in a considerable amount of the moisture being thrown out, andthe reverse flow through an arc of 90 in going from the steam Thedisposition of the battles in the manner,

described permits of the same sections being used for hot water heatingsystems where the entire section is filled with water, as it does notrestrict the circulation of the water in such case, andby reason of the:inclination or curvature sediment would not accumulate on it to anundesirable extent. Thus the boiler sections are readily adapt-. ed foruse in either type of heating plant, notwithstanding the presence ofthese baffles.

While I have shown and described a particular boiler section and aparticular location of the battles in regard to this specific section,it will be understood that the invention may be otherwise embodied andthat various changes and modifications may be made within'thecontemplation of the appended claim.

A- boiler section havingan upper portion forming a combined steam andwater chamber the water line of the boiler defining the separation of the steam and water chambers, a nipple: port on a side face of thesectionopeningintotthechamber, the normalwater line beingabove the. bottom ofthe nipple port, a centrally located ing spaces, said baffles beinggenerally inclined:

upwardly and-outwardly, away. from the center of the section, thelowerends of thegbaffiesnearest. the center, of v. the section terminating.below the water line ofthe boiler section,- the upper outer ends of thebafiles terminating, in the steam, space below the top of the sectionand inwardly from the side thereof, the, arrangement being. such thatsteam generated below the baffles is directed in a generallyhorizontaldirection away from the center of the, boiler and then turnsat an angle of approximately 180 back toward the? center of the boilerand is furtherdeflected through a reverse angle ofapproximatelyBO? inpassingto the ofitake. I

, LOUIS N. HUNTER.

